Self-ventilated dynamoelectric machine having an air cleaner



Patented Apr. 1, 1952 SELF-VENTILATED DYNAMOELECTRIC MACHINE HAVING ANAIR CLEANER John H. Crankshaw, Erie, Pa., assignor to General ElectricCompany, a corporation of New York Application September 3, 1949, SerialNo. 113,987

9 Claims.

This invention relates to dynamoelectric machines of the self-ventilatedtype and more particularly to dynamoelectric machines having a dirtseparating air cleaner, for example, traction motors.

Railway traction motors are commonly mounted either on the truck properor partially supported by the axle. This location is particularly dirtyin operation and, since traction motors are usually of the air cooledtype, it is necessary to restrain dirt, dust, snow and other objectsfrom entering the motor and thus causing sticking of the brushes in theholders, insulation damage, and adversely affecting heat transfer to thecooling air. In the past, cooling air has been taken from inside thebody of the vehicle, thus obtaining cleaner air, but introducing manyproblems in duct design. It is, therefore, desirable in the design ofsome types of traction motors to provide a self-ventilated motor havingits own fan for drawing ventilating air through the machine. However, inapplications where the car or locomotive is operated over dirty roadbedin which the ballast consists of a considerable amount of cinders andsand, it has been found that the dirt blown up by the rapid motion ofthe vehicle and drawn into a self-ventilated motor will sand blast theinsulation completely off the corners of the field coils and erode thecopper winding. It is, therefore, desirable in the design ofself-ventilated traction motors to provide air cleaning means which willpresent low restriction to the entrance of ventilating air into theinterior of the machine, but which will separate a maximum amount of thedirt from the air before it is passed through the machine.

An object of this invention is to provide an improved dynamoelectricmachine having a dirt separating air cleaner.

A further object of this invention is to provide an improveddynamoelectric machine having a dirt separating air cleaner wherein lowrestriction is presented to the entrance of air into the motor and themaximum amount of dirt is separated from the air before it enters themotor.

Further objects and advantages of this invention will become apparentand the invention will be better understood from the followingdescription referring to the accompanying drawings, and the features ofnovelty which characterize the invention will be pointed out withparticularity in the claims annexed to and forming part of thisspecification.

In accordance with one aspect of this invention, a cover is provided on.the end of the motor remote from the fan having a plurality of louveropenings formed therein for admitting the ventilating air to theinterior of the machine. A curved scroll passage surrounds a part of thecover and communicates with the louver openings. The scroll passage hasa converging configuration with its large end open to the atmosphere forcollecting air and the passage is arranged so that the louver openingsare adjacent the small end so that the ventilating air enters thepassage at low velocity and is accelerated toward the louver openings.The louver openings face away from the exterior opening of the scrollpassage so that the ventilating air must make a sharp bend to enter theinterior of the motor. contained in the air, having. been accelerated byvirtue of the converging configuration of the scroll passage, due to itsgreater mass does not enter the louver openings but continues toward thesmall end of the scroll passage. The louvers are arranged so that dirtcascades thereover under the influence of gravity into the small end ofthe scroll passage. Another air passage is provided having a convergingconfiguration with its large end arranged to collect a part of the airdischarged by the fan and its small end open to the atmosphere. Thesmall end of the scroll passage communicates with the small end of thesecond air passage to form an aspirator, the air collected from the fanbeing accelerated over the small end of the scroll passage to suck theseparated dirt out of the scroll passage and to blow the dirt into theatmosphere. In accordance with a further aspect of this invention, aVenturi tube is substituted for the second air passage to provide theaspirator for sucking dirt out of the scroll passage.

In the drawing, Fig. 1 is a view in perspective, partly in section,illustrating the improved dirt separating air cleaner of this invention;Fig.2 is an end view, partly in section, illustrating a modified form ofthis invention; and Fig. 3 is a side elevational view of the embodimentof Fig.2.

Referring now to Fig. 1, there is shown atraction motor I having a shaft2 adapted to drive the vehicle in any conventional manner. motor I isprovided with a fan, shown at l5,'at one end thereof for drawingventilating 'air through the interior of the motor and a shroud andbafile assembly 3 surround the fan to form a fan outlet. In order toprovide for the admission of ventilating air into the interior of themotor under the influence of the fan and to separate dirt contained inthe air prior to its entrance into the motor, the arrangement now to bedescribed Thus, the dirt- The is provided. A'cylindrical cover member lis arranged on the end of the machine remote from the fan, usually thecommutator end, and is provided with a plurality of louver openings foradmitting ventilating air into the interior of the machine. A curvedconverging scroll passage 6 is arranged surrounding a part of the covermember 4 and communicating with the louver openings 5 for directing theventilating air thereto. The scroll passage 5 has an exterior airentrance opening 1 formed at its large end, which opening may be coveredby a coarse mesh screen 8 for preventing the entry of very largeparticles such as leaves, sticks, etc. The scroll passage 8 ispositioned so that the louver openings 5 are adjacent its small end 9and the louver openings are arranged so that they face away from theexterior opening I and toward the small end 9 of the scroll passage 6.By virtue of the converging configuration of the scroll passage 8,ventilating air enters the exterior opening I at low velocity and isaccelerated toward the louver openings 5. Since the louver openings 5face away from the opening 'i, the ventilating air is required to make asharp bend to enter the interior of the motor. The acceleration of theair in the scroll passage 6 forces some of the entrained dirt againstthe outer surface of the scroll passage by centrifugal force.Furthermore, the air is able to negotiate the sharp bend into the louveropenings while the dirt, because of its greater mass, continues towardthe small end 9 of the scroll passage 6. The louvers 5 are arranged sothat the heavy particles of dirt which may fall cascade thereover underthe force of gravity into the small end 9 of the scroll passage 6without entering the openings. The combined action of these threefunctions causes a large portion of the dirt contained in the air drawninto the opening 1 to enter the small end 9 of scroll passage 6 ratherthan entering the louver openings 5.

In order to exhaust the dirt collected in the small end 9 of the scrollpassage 6 into the atmosphere, another air passage it is provided havinga converging configuration withits large end H arranged to collect aportion of the air exhausted by the fan through the fan outlet 3 and itssmall end 12 open to the atmosphere. The small end 9 of the scrollpassage E communicates with the air passage ll) adjacent its small endl2. The converging configuration of the air passage iii accelerates theair collected from the fan over the opening 9 of the scroll passage 6 sothat a vacuum is produced at this point due to its effect as anaspirator. Thus, the dirt in the small end 9 of scroll passage 6 issucked out of the scroll passage and blown into the atmosphere out of asmall end 12 of the air passage in. It will be readily apparent thatthis air cleaning construction is applicable not only to tractionmotors, but to any self -ventilated machine.

It may be found that the ventilating fan will not produce sufficientpressure to provide for eflicient separation of dirt or, particularly inthe case of a traction motor, the construction of the air passage italong the frame of the motor may rangement, the Venturi tube !3 isoriented in a direction parallel to the direction of travel of thevehicle so that the motion of the vehicle forces air into the Venturitube l3 producing a, vacuum at the small end 9 of the scroll passage 6to suck out the dirt and to blow it into the atmosphere. It will bereadily apparent that this embodiment is operable in either direction ofvehicle motion so that a motor equipped with this air cleaner would becompletely interchangeable for either truck position or for eitherdirection of vehicle motion.

Tests made with an air cleaner of the type disclosed above indicate thatthe cleaning efficiency based on the Weight of the dirt separated ascompared with the total weight of the dirt introduced at the opening 'Iis or better. It will now be seen that this invention provides animproved air cleaner for self-ventilated apparatus, particularlytraction motors, which separates and discharges to the atmosphere asubstantial quantity of the dirt contained in the cooling air withoutpermitting the dirt to enter the interior of the machine.

While I have illustrated and described particular embodiments of thisinvention, modifications thereof will occur to those skilled in the art.I desire it to be understood, therefore, that this invention is not toto be limited to the particular arrangements disclosed, and I intend, inthe appended claims, to cover all modifications which do not depart fromthe spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. A self-ventilated dynamoelectric machine comprising a fan for drawingventilating air therethrough, a cover member for said machine having anopening formed in its peripheral surface at one end thereof foradmitting ventilating air to said machine under the influence of saidfan and a second opening formed in its peripheral surface at the otherend thereof for discharging air from said machine, a passage memberhaving an air entrance at one end thereof and communicating with saidfirst opening for directing air thereto, a second passage member havingone end communicating with said second opening for collecting airdischarged from said machine and its other end communicating with theother end of said first passage member for sucking dirt out of saidfirst passage member and for blowing said dirt into the atmosphere.

2. A self-ventilated dynamoelectric machine comprising a fan for drawingventilating air therethrough, a cover member having a louver openingformed in its outer periphery at one end thereof for admittingventilating air to said machine under the influence of said fan andanother opening formed in its outer periphery at the other end thereoffor discharging air from said machine, a passage member having an airentrance at one end thereof and communicating with said louver openingfor directing air thereto, said louver having its opening facing awayfrom said air entrance so that ventilatingair is required to make asharp bend when entering said machine whereby dirt contained in saidventilating air due to its greater mass does not enter said louveropening but continues into the other end of said passage member, and asecond passage member having one end communicating with said otheropening for collecting air discharged therefrom and its other endcommunicating with said other end of said first passage member forsucking dirt out of said other end of said first passage member and forblowing said dirt into the atmosphere.

3. A self-ventilated dynamoelectric machine comprising a fan for drawingventilating air therethrough, cylindrical cover member having aplurality of louver openings formed in its peripheral surface at one endthereof for admitting ventilating air to said machine under theinfluence of said fan and a plurality of other openings formed in itsperipheral surface at the other end thereof for discharging air fromsaid machine, a scroll passage member surrounding part of the peripheralsurface of said cover and communicating'with said louvers for directingair thereto, said passage member having an air entrance at one endthereof, saidlouver openings facing away from said air entrance so thatsaid ventilating air is required to make a sharp bend when entering saidmachine whereby dirt contained in said air due to its greater mass doesnot enter said louver open-- ings but continues toward the other end ofsaid passage member, said louvers being arranged so that said dirtcascades thereover under the influence of gravity into said other end.ofsaid passage member, and a second passage member having one endcommunicating with at least a part of said other openings for collectingair discharged therefrom and its other end communicatirig with saidother end of said first passage member for sucking dirt out of saidother end of said first passage member and for blowing said dirt intothe atmosphere.

4. A self-ventilated dynamoelectric machine comprising a fan for drawingventilating air therethrough, a cover member having a plurality oflouver openings formed in its peripheral surface at one end thereof foradmitting ventilating air to said machine under the influence of saidfan and a plurality of other openings formed in its peripheral surfaceat the other end thereof for discharging air from said machine, apassage member communicating with said louvers and having a convergingconfiguration with an air entrance formed at the large end thereof, saidpassage member being positioned so that said louvers are adjacent thesmall end thereof whereby air enters said passage member at low velocityand is accelerated toward said louvers, said louver openings facing awayfrom said air entrance so that said ventilating air is required to makea sharp bend when entering said machine so that dirt contained in saidair due to its greater mass does not enter said louver openings butcontinues to small end of said passage member, and a second passagemember having one end communicating with at least a part of said otheropenings for collecting air discharged therefrom and having its otherend communicating with said small end of said first passage member forsucking dirt out of said small end of said first passage member and forblowing said dirt into the atmosphere.

5, A self-ventilated dynamoelectric machine compring a fan for drawingventilating air therethrough, a cylindrical cover member for saidmachine having a plurality of louver openings formed in its peripheralsurface at one end thereof for admitting ventilating air to said machineunder the influence of said fan, and a plurality of other openingsformed in its pcripheral surface at the other end thereof fordischarging air from said machine, a curved scroll passage membersurrounding a part of the peripheral surface of said cover andcommunicating with said louvers, said passage member having a convergingconfiguration with an air entrance at its large end, said passage memberbeing positioned so that said louvers are adjacent the small end thereofwhereby air enters said passage member at low velocity and isaccelerated toward said louvers, said louver openings facing away fromsaid air entrance so that said ventilating air is required to make asharp bend when entering said machine whereby dirt contained in saidventilating air due to its greater mass does not enter said louveropenings but continues toward the small end of said passage member, saidlouvers being arranged so that said dirt cascades thereover into saidsmall end of said passage member under the influence of gravity withoutentering said openings, and a second passage member having one endcommunicating with at least a part of said other openings for collectingair discharged therefrom and its other end communicating with said smallend of said first passage member for sucking dirt out of said small endof said first passage member and for blowing said dirt into theatmosphere.

6. A self-ventilated dynamoelectric machine having a fan at one endthereof for drawing ventilating air therethrough, a cover member havinga louver opening formed in its peripheral surface at the end remote fromsaid fan for admitting ventilatin air to said machine under theinfluence of said fan and another opening in its peripheral surface atthe end adjacent said fan for discharging air fromsaid machine, apassage member having an air entrance at one end thereof andcommunicating with said louver for directing ventilating air thereto,and a second passage member having one end communicating with said otheropening for collecting air discharged therefrom and its other end openedto the atmosphere, the other end of said first passage membercommunicatin with said second passage member so that said air collectedfrom said other opening is passed over the other end of saidfirst-mentioned passage member whereby said second passage member actsas an aspirator for sucking dirt out of said first-mentioned passagemember and for blowing said dirt into the atmosphere.

'7. A self-ventilated dynamoelectric machine having a fan at one endthereof for drawing ventilating air therethrough, a cylindrical covermember having a plurality of louver openings formed in its peripheralsurface at the end remote from said fan for admitting ventilating air tosaid machine under the influence of said fan and a plurality of otheropenings formed in its perpiheral surface at the end adjacent said fanfor discharging air from said machine, a passage member communicatingwith said louvers and having a converging configuration with an airentrance at its large end, said passage member being arranged so thatsaid louvers are adjacent the small end thereof whereby air enters saidpassage member at low velocity and is accelerated toward said louvers,and a second passage member communicating with at least a part of saidother openings for collecting air dischargedtherefrom and having itsother end open to the atmosphere, the small end of said first-mentionedpassage member communicating with said second message member, saidsecond passage member converging :from said one end toward said other=.-from said fan for admitting ventilating air to said machine under theinfluence of said fan, and a plurality of other openings formed in itsperipheral surface at the end adjacent said fan for discharging air fromsaid machine, a curved scroll passage member surrounding a part of saidperipheral surface of said cover and communicating with said louvers fordirecting air thereto, said passage member having a convergingconfiguration with an air entrance at its large end and being positionedso that said louvers are adjacent its small end whereby air enters saidpassage member at low velocity and is accelerated toward said louvers,said louvers being arranged with their openings facing away from saidair entrance so that said ventilating air is required to make a .sharpbend when entering said louver openings whereby the dirt contained insaid air due to its greater mass does not enter said louvers but con-,tinues toward said small end of said passage ,member, said louversbeing arranged so that said dirt cascades thereover under the influenceof gravity into said small end of said passage mem ber without enteringsaid louver openings, and an air passage member having one endcommunicating with at least a part of said other openings for collectingair discharged therefrom, said small end of said scroll passage membercommunicating with said last-named passage member adjacent its endremote from said other openings, said ,remote'end of said last-namedpassage member being open to the atmosphere, said last-named passagemember converging from said one end toward said open end foraccelerating the air collected from said other openings over said smallend of said scroll passage member whereby said last-named passage memberacts as an aspirator for sucking dirt out of said small end of saidscroll passage member and for blowing said dirt into the atmosphere.

9. A self-ventilated dynamoelectric machine comprising a fan at one endthereof for drawing ventilating air therethrough, a cover member havinga louver opening formed in its peripheral surair to said machine underthe influence of said fan and another opening formed in said peripheralsurface at the other end thereof for discharging therefrom said machine,a passage member communicating with said louver for admittingventilatingair thereto, said passage member having a convergingconfiguration with an air entrance at its large end and being positionedso that said louver is adjacent the small end thereof whereby air enterssaid passage member at low velocity and is accelerated toward saidlouver, said louver opening facing away from said air entrance so thatsaid ventilating air is required to make a sharp bend when entering saidlouver opening whereby the dirt contained in said air due to its greatermass does not enter said louver but continues toward said small end ofsaid passage member, said louver being arranged so that said dirtcascades thereover into said small end of said passage member under theinfluence of gravity without entering said louver opening, and anotherpassage member having one end communicating with said other opening forcollecting air discharged therefrom, said small end of saidfirst-mentioned passage member communieating with said last-namedpassage member adjacent its end remote from said other opening, saidremote endof said last-named passage member being open to theatmosphere, said lastnamed passage converging from said one end towardsaid open end for accelerating the air collected from said other openingover said small end of said first-named passage member whereby saidlast-named passage member acts as an aspirator for sucking dirt out ofthe said first-mentioned passage member and for blowing said dirt intothe atmosphere.

JOHN H. CRANKSHAW.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,530,645 Brockway Mar. 24, 19251,620,241 Stebbins Mar. 8, 1927 1,745,950 Orem Feb. 4, 1930 2,087,789Allardice July 20, 1937 2,182,862 Allardice Dec. 12, 1939 2,327,197Lincoln Aug. 17, 1943"" FOREIGN PATENTS Number Country Date 539,188Great Britain Sept. 1, 1941 627,213 Germany Mar. 11, 1936

